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EXPERIMENT STATION 

OF THE 

HAWAIIAN SUGAR PLANTERS' ASSOCIATION 



The Improvement of Plants 
Through Bud Selection 



BY 



A. D. SHAMEL 

Physiologist of the U. S. Department of Agriculture 



HONOLULU, HAWAII 



EXPERIMENT STATION 

OF THE 

HAWAIIAN SUGAR PLANTERS' ASSOCIATION 



The Improvement of Plants 
Through Bud Selection 



A. D. SHAMEL 

Physiologist of the U. S. Department of Agriculture 



HONOLULU, HAWAII 



3^\"2-^ 



.S^ 



LETTER OF TRANSMITTAL 



To the Experiment Station Cuniinittee of the 
Hawaiian Sii(/ar Planters' Assoeiation, 
Honolulu, r. H. 

Dear Sirs : — 

I transmit herewith for pubHcation a paper by Mr. A. D. Shamel, Physiolo- 
gist of the U. S. Department of Agriculture, entitled "The Improvement of 
Plants Through Bud Selection." This paper was presented by Mr. Shamel at a 
meeting of the Social Science Association of Honolulu, March 7, 1921, and is 
published through the courtesy of that organization. 





Respectfully, 




H. P. Agee. 


am 


Director. 


"^'.blicher 




m 7 1922 





PREFACE 



The present paper was prepared at the suggestion of Mr. Alonzo Gartley 
for presentation to the members of the Social Science Association of Honohilu. 
After reading, the members of this Association kindly consented to the request of 
Mr. H. P. Agee that it be published by the Experiment Station of the Hawaiian 
Sugar Planters' Association. In this paper the writer has attempted to briefly 
present his point of view and experience in the work for the improvement of 
certain economic plants through bud selection. His experience has covered about 
twenty years of active work with plant improvement, mainly with corn, tobacco, 
asparagus, citrus fruits, and some other farm crops. Individual sugar cane plant 
studies were begun in February, 1920, by the writer and associates of the 
Experiment Station of the Hawaiian Sugar Planters' Association. The writer 
believes that the results of this effort will be of particular scientific interest and 
great commercial importance. 

A. D. Shamel. 

March 12, 1921. 



CONTENTS 



Page 

Plant Improvement 1 

Definition of the Terms Bud Variation anil Bml Selection 2 

Objects of Bu.l Selection 4 

The Origin of Varieties- from Bud Mutations 4 

The Isolation of Strains in Established Varieties 12 

The Elimination of Undesirable Strains 15 

The Amelioration of Varieties and Strains Through Bud Selection lo 

Individual Plant Performance Eecords 16 

The Commercial Utilization of Individual Plant Records 20 

The Selection of Superior Parent Plants 21 

Progeny Tests 21 

The Scientific Study of Bud Mutations and Bud Selection 22 

Pioneers in Bud Mutation and Selection Work 22 

Summary 23 

Literature Cited 24 

Explanation of Plates 27 



The Improvement of Plants Through Bud 
Selection 

Plant I.mpron'Ement. 

We are indebted to Charles Darwin for much of our knowledge of the be- 
havior of animals and plants under domestication (14, 15). His investigations 
established many of the principles of, and laid the foundation for, the further 
scientific study of organic evolution. The records of his observations and experi- 
ments with plants have furnished a large amount of fundamentally important 
data and reliable information which has constituted the basis for much of the 
recent constructive work for plant improvement. He states that the conscious 
or unconscious selection of superior plants for propagation by man has been 
carried on for about as long a time as agriculture has existed. He found in 
ancient Chinese encyclopedias ( 15 ), translated by the Jesuits in the 18th cen- 
tury, records of recommendations for the preservation and propagation of the 
best plants, the choice of large seeds for planting, and the history of an improved 
variety of rice secured through the selection and propagation of superior plants 
by the Emperor Khang-hi. Rice is one of the best examples of the value of plant 
improvement work. At the present time there exist more than 5,000 local varie- 
ties in different rice-growing districts of the world which have been developed 
through plant selection and propagation. 

The sexuality of plants was demonstrated by Camerarius in 1691. The first 
hybrid of which we have a record was made by Thomas Fairchild, an English 
gardener, in 1719. Knight, an eminent English student of plant life, contributed 
a large amount of information to our knowledge of plant hybridization. Van 
Mons, a Belgian horticulturist, produced a number of improved varieties of plants 
through selection. 

The re-discovery of Mendel's famous law in 1900 (3) and the publication 
of De Vries' mutation theory in the following year (72) marked a new era in 
plant improvement. These contributions stimulated a widespread interest in the 
study of plant improvement which has been unequaled in the history of agricul- 
ture. A large number of investigators are now devoting their entire time and 
energy to a study of the various phases of this subject. Many universities have 
inaugurated courses of instruction and study for students along these lines. A 
number of research institutions have been established in the United States and 
abroad for the purpose of investigating the fundamental principles underlying 
the work of plant improvement. Several commercial organizations have been 
built up for the sole purpose of carrying on practical plant improvement work for 
particular crops. As a result of this intensive and systematic activity, plant im- 
provement has become a subject of great scientific interest and large commercial 
importance during recent years. 

Much of the pioneer work for plant improvement has been carried on with 
sexually reproduced plants. In science, sex, fecundation and the behavior of 
hybrid plants have received the major share of attention. In practice, seed se- 
lection has been the most important phase of plant improvement work. While 



it has been known for a long time that bud variation occurs in vegetatively propa- 
gated plants, the study of this phenomenon has been somewhat neglected for 
several reasons. It has been quite generally believed that when an asexually 
propagated variety has become established no further selection is necessary. The 
reasons for, and the necessity of, selection of plants grown from seed have become 
matters of common knowledge. On the other hand, the causes of bud variations 
are not fully understood as yet, the extent and frequency of this phenomenon 
have not been determined except in the case of a few plants, and the facts con- 
cerning tlie importance of bud variation and bud selection in the amelioration of 
plants are not widely understood. Furthermore, the scientific study of seeds 
produced under controlled conditions and of the behavior of the plants grown 
from them provides particularly convenient and fascinating material for investi- 
gation and demonstration. The results of such study have often been extremely 
spectacular and have attracted a deservedly vital interest in the minds of the 
general public. These and other related conditions have naturally led to a con- 
centration of interest, both from the scientific and commercial standpoints, in 
this phase of plant improvement and to a lack of interest in similar work with 
vegetatively propagated plants. The purpose of this paper is to present evidence 
to show that bud variations are of frequent occurrence in many plants and to 
suggest the importance of bud selection in the economic improvement of those 
plants. This discussion will be largely confined to the practical application of 
bud selection work in the improvement of certain agricultural crop plants which 
are of commercial value and importance and which are propagated without refer- 
ence to sexual reproduction. 

Definition of the Terms Bud \'.\ri.\tion .and Bud Selection. 

The term bud variation, as we understand it, applies to any variations that 
take place in the soma of the plant as distinguished from the variations appar- 
ently caused by sexual reproduction and shown by the behavior of seedlings. 
Webber states {77) in this connection * * * "from our present knowledge 
of the cytology of heredity we would assume that hereditary changes such as 
those manifested by bud variation, as well as seedling variations, are due to re- 
arrangements of the hereditary units or anlagen which occur during cell division. 
In the case of seedling variation we assume that this rearrangement takes place 
primarily during the progress of the reduction division that precedes the forma- 
tion of sexual cells. So far as microscopic investigations go we have no evi- 
dence that would strengthen the idea of such a redistribution of characters ever 
taking place in somatic cells. However, we have the strongest of all possible 
proofs that it does occur in the fact that in bud variation we get segregations of 
character analogous to the segregations of seedlings." 

Bud variations may be divided into two general classes : { 1 ) those which are 
not inherited and (2j those which are inherited. The non-heritable variations 
include that type of variation which is the result of environmental influence and is 
exhibited in the response of all kinds of plants in the same definite way to the 
stimulation of environmental factors. 



In this discussion we are concerned primarily with the types of bud variations 
which are inherited. These types may be conveniently divided into two classes, 
(a) bud fluctuations or continuous bud variations and (b) bud mutations or dis- 
continuous bud variations. Castle defines fluctuations as "those which are purely 
quantitative, plus or minus, as compared with the prevailing racial condition" (10). 
The value of bud fluctuation or continuous bud variations in the work of plant 
improvement is a matter of dispute amongst some investigators. The particular 
point at issue seems to be the possibility of changing the mode or increasing the 
ma.ximum through the continuous selection of maximum bud fluctuations. The 
experience and observations of the writer have led him to believe that by con- 
tiiuious selection in isolated strains the mean of the variation in the selected popu- 
lation may be raised to a point more nearly approximating the maximum exhibi- 
tion of the character in the strain. This conclusion has been reached as the 
result of study and observations in the amelioration of several of our important 
economic plants, among which may be mentioned the increase of the average 
percentage of oil, protein, and starch in the composition of maize through the 
systematic selection of seed possessing the maximum amoiuits of these elements 
in their composition ; the increase in the yield of varieties of tobacco through the 
systematic selection of seed from the best individual plants ; the increase in yield 
of violets through the selection and propagation of cuttings from the most pro- 
ductive plants ; the increase in the yield of potatoes by the selection of tubers from 
the high-yielding hills ; the improvement in the yield of citrus fruits through the 
propagation of the best-yielding parent trees ; and many other equally striking 
similar experiences. It is argued by some of the opponents to this conclusion 
that even if these improvements in plant behavior have been effected it will be 
necessary to continue the selection by means of which they were secured in order 
to preserve and maintain them. This idea may or may not be correct, and even 
granting that it may be sound in some cases, it does not vitiate the fundamental 
importance of selection in developing and maintaining improved production. It 
is the personal opinion of the writer that through the selection of observed bud 
fluctuations in any plant character, such as size, number, or chemical composi- 
tion, those of genetic character will be included so that through repeated selec- 
tion races will be developed which are progressively larger, more productive, or 
otherwise changed in the direction of the selection. From the commercial stand- 
point it is thought that this phase of plant breeding is the most important one 
concerned in the work for the improvement of plants. 

The terms bud mutation.s or discontinuous bud variations in this discussion 
will be used to define sudden or marked variations from the parental forms in 
vegetatively propagated plants. Darwin called such variations bud sports, but 
this term has been largely superseded by the term bud mutation as proposed by 
De Vries. Many of our valuable varieties and strains of cultivated plants have 
originated from bud mutations. It is probable that amongst vegetatively propa- 
gated plants a majority of the important commercial varieties have originated in 
tills way. In seed propagated plants, it is the writer's conviction that a consid- 



crable number of important varieties, which are commonly thought to have arisen 
from crossing, have, as a matter of fact, originated as bud mutations. 

The term bud selection as used in this paper may be defined as the selection 
and propagation of heritable bud variations which, for one reason or another, are 
better suited for cultivation than the parent plants. Bud variations are of no 
value in the work for the improvement of plants unless they are preserved and 
propagated. Hieir preservation depends wholly upon selection. It naturally 
follows, then, that bud selection is the agency through which bud variations are 
perpetuated and utilized in the work of plant improvement. 

Objects of Bud Selection. 

The fundamental objects of bud selection in the work of plant improvement 
may be classed as follows : ( 1 ) to secure new and better varieties of plants 
through the selection and propagation of striking and valuable bud mutations ; 
(2) to isolate strains of established varieties which show characteristics of greater 
merit or value than those of the parent varieties; and (3) to bring the average 
performance of the population of a strain or variety up to that exhibited by the 
maximum individual performance or as nearly so as is found to be practical. 

The' (3rigix of \".\rieties from Bud Mutations. 

An impressive number of important cultivated varieties of plants are defi- 
nitely known to have originated from bud mutations (8, 13, 13). This number is 
probably only a small fraction of the actual total number of valuable varieties 
which have originated in this way. This condition arises from the fact that 
many of the supposed variations in seedlings which have been selected and propa- 
gated as new varieties were dotibtless the result of the seeds having come from 
different branches of the parent plants. These branches as a result of bud 
variations transmitted to the seeds their different tendencies which were discov- 
ered as variations in the plants grown from these seeds. In such instances the 
originators of the varieties propagated from such selected variations have often 
assumed that the variations were the result of hybridization or other sexual 
influences, when as a matter of fact they are actually the result of bud variation. 

It will be possible in this paper to refer to only a small number of the known 
cases of valuable varieties of plants which have originated from bud mutations. 
A few typical instances in different plant groups will be cited in order to empha- 
size the importance of this factor in plant improvement work and to indicate 
something of the possibilities of further effort along this line. 

Many varieties of roses have originated from bud mutations. Carriere (8) 
gives in his account of bud varieties published in 1865 a list of fifty standard 
rose varieties known to have originated from bud mutations and states that no 
attempt was made to make the list complete. The 1919 Annual of the American 
Rose Society contains a list (25) of 429 varieties of American roses, of 
which 116. or more than 25 per cent, are definitel}- known to have originated from 
bud mutations, for the most part within the past twenty-five years. Carriere (8) 



and Darwin (15) both present evidence, which has been confirmed repeatedly, 
that the moss rose varieties have originated from bud mutations and, in turn, 
smooth branch varieties have sprung from moss varieties through bud variations. 
For example, the common doul^le moss rose originated from the smooth-bran 
Provence rose by bud variation. The moss rose has produced the Provence rose 
in which the branches are partially or wholly destitute of moss. 

From the Killarney rose, solid pink in color, a large number of varieties 
have been secured through the selection of bud mutations (38). These bud varie- 
ties have differed in color from white to red, in flower arrangement from semi- 
doubles to doubles, and in habit of growth from bush to climbing forms. Amongst 
these varieties may be mentioned the White Killarney, Dark Pink Killarney, 
Ciiamp Weiland, Killarney Queen, Double White Killarney, Double Pink Killar- 
ney, Red Killarney, Killarney Brilliant, Climbing Killarney (pink), and Climbing 
\\ hite Killarney. 

The (_)phelia, a pink rose, is a variety of comparatively recent introduction 
which is c'eserx'edly popular at the present time. This variety is very prolific in 
the ])roduction of bud mutations (71), the most important of which include the 
Ophelia Supreme, having Hght rose-pink flowers ; Rosalind, with coral-pink 
flowers, changing to apricot-pink ; Silvia, having sulphur-yellow flowers, changing 
to creamy shaded ; Evelyn, with larger flowers of a deeper shade and larger 
blooms ; Rose Pink Ophelia, having smaller flowers but flowering more freely 
than the Ophelia ; May Martin, with mustard-yellow flowers ; Madame Butterfly, 
with flowers of greatly intensified color ; White Ophelia, having white flowers ; 
and other varieties with flowers of varying shades of color and difl^erent types 
of foliage. 

The rose varieties having a climbing habit of growth have practically all 
originated as bud mutations from bush forms (25). Examples of this phenome- 
non include the Climbing Bridesmaid, the Climbing Cecile Briinner, the Climbing 
Frau Karl Druschki, the Climbing La France, and the Climbing Rhea Reid. The 
1919 Annual of the American Rose Society contains a list of 34 climbing varie- 
ties of recent American origin which have been propagated from bud muta- 
tions {2? \. 

In chrysanthemums, a large proportion of the present cultivated varieties 
have originated from bud mutations. Cramer (13) presents a list of 400 bud 
varieties of the chrysanthemum. From this list of bud varieties the following 
examples are presented : 

Parent Variety. Bud Variety. Autliority. 

Aleester (Lord), 1882. Mr. Robert Murdie, 1888. The Garden, 90, I, 145. 

Inflected, butter-yellow. Inflected, salmon-yellow. 

Andiguier (Edward), 1886. Mrs. William Walters, 1887. The Garden, 88, II, 498. 

Jap., brown, purple, Jap., Carmine, 

silver back. bronze-gold back. 

Avalanche, 1887. Edw. Beckett, 1892. de Meulenaese, II, 49. 

Snow-white. Jap., dark gold-yellow. 



In 1822, twenty-seven varieties of chrysanthemums were cultivated in Eng- 
land, part of which had been imported, and some of which had originated from 
the imported varieties through bud mutation. In 1836 three Chinese varieties 
were imported which bore pink, speckled, and flesh-colored flowers, respectively. 
The next year a single plant bore all three of these forms. 

Chrysanthemum bud mutations frequently occur in the branches of the 
plants and occasionally in the suckers. They may be propagated in either form. 
The stability of the bud mutations must be determined by experimental propa- 
gations unless it is a type which is known to be transmitted. The practicability 
of this effort is shown by the fact that of the 8,800 varieties cultivated in Europe 
in 1899 more than .\000 were originated in this way. 

In carnations, many of the valuable cultivated varieties have originated as 
bud mutations. Dorsey (18) mentions among the important commercial bud 
varieties the Victor, Chicago, White Lawson, White Enchantress, Rose Pink 
Enchantress and Enchantress Supreme. 

In hibiscus, Darwin ( 1.^) mentions several striking bud mutations, inchiding 
one where the bud variation produced flowers and leaves resembling in shape 
those of another species. Both the parental form and the bud mutation were 
extensively propagated by cuttings and came perfectly true. Stout (69) records 
tile origin of a dwarf form of Hibiscus pcnliroseus as a mutation. Carriere (8) 
cites two instances of varieties of hibiscus originating from bud mutations, viz., 
H. syriacus, variety flare plena I'lirief/ata, with variegated yellowish-white 
leases, appearing in a green-leaved plant in 18.t8, and H. s\riaeiis. variety varie- 
gata, with remarkably variegated leaves, an example of which is shown in Plate I. 
While in Honolulu in 1920 the writer's attention was called to several cases of 
bud mutation in hibiscus plants, including double flowers borne by single-flower 
plants and the development of branches having very different foliage on the same 
stem. 

In dahlias, Darwin (13) cites the case of the Butterfly variety, in which the 
same plants produced double and single flowers, "here white petals edged with 
maroon, there of a uniform deep maroon." He also records the instance of a 
plant which bore two different kinds of self-colored flowers as well as a third 
kind which partook of both colors beautifully intermixed. Similar illustrations 
of bud mutations in dahlias have been repeatedly observed in gardens in southern 
California during recent years by the writer, an example of which is shown in 
Plate 2. The Le Grand Manitou, a leading dahlia variety having white flowers 
with purple stripes, has produced a purple-flowered variety, the Purple Manitou, 
as shown in Plate 3, by liud mutation which is being cultivated at the jjresent time 
to some extent. 

Many other instances of varieties of conmion flowering plants arising from 
bud mutations might be mentioned. Bud varieties of the Sweet William, Snap- 
Dragon, Stocks, Cyclamen, Gladiolus, Fuchsia, Violet, Hydrangea, Geranium, 
and Evening Primrose are widely cultivated by gardeners and florists. We be- 



lieve, however, that the examples already given are sufficient to show the im- 
portance of this phenomenon in the work for the improvement of flowers. 

With ornamental plants the selection and propagation of bud mutations has 
provided a large number of valuable varieties for cultivation. 

The Euonymus varieties are amongst the most valuable and widely grown of 
all ornamental plants. Carriere (8) calls attention to five bud varieties of 
E. Japonica. viz., argcntea, aurca, flavida. fasciata, and calamistrata, and states 
that many other varieties which diflfer in variegation or sometimes by the form of 
leaves have been produced by the selection and propagation of bud mutations. 

Roeding (46), one of the leading plant propagators in California, propagates 
and distributes the following varieties of E. Japonica which he personally told the 
writer in August, 1919, were originated from bud mutations : AWo-marginata 
(silver-margined), albo-variegata (silver-variegated), aurco-ivricgata (golden- 
variegated), columnaris (tall-growing), viridi-variegata (Due dWnjou), aureo- 
marginata (golden-margined), and inicrophylla (dwarf form). The writer 
recentlv has found all of these variations occurring as bud mutations in Euony- 
mus plants growing in the vicinity of Riverside, an example of which is shown 
in Plate 4. and has complete evidence as to the origin of the above mentioned 
cultivated varieties from Inid variations. 

Pittosporuni varieties are now widely grown as ornamental lawn ]5lants and 
for shrubbery. They rank in importance in this respect with the Euonymus 
varieties. Carriere (8) mentions that P. Tobira variegatmn originated from 
P. Tobira as a bud mutation. This variegated-leaved variety is one of the most 
popular ones in California and has been repeatedly found by the writer (52) 
occurring as bud mutations in the green-leaved parental form. Other mutations 
of P. Tobira, differing in leaf-form and variegation, have been observed by the 
writer in plants growing in the vicinity of Riverside, California, an example of 
which is shown in Plate 5. Some of these have been isolated through bud selec- 
tion and are now being cultivated to an increasing extent, an illustration of which 
is shown in Plate 6. 

In Coleus, Stout (70) found that bud variations are common and give rise 
to numerous different types which may be quite constant from the first or can be 
made so by selection. In pedigree cultures he isolated 15 distinct varieties through 
bud selection which were characteristically different in color patterns. He con- 
cludes from his investigations that in Coleus asexual and sexual reproduction 
are not fundamentally different in respect to the extent and range of variation. 

In ferns, Boshnakian (6) states that in the common Boston fern (Nephro- 
lepis exaltata bostoniensis ) over 65 commercial varieties have originated as bud 
mutations since 1898. 

In the Oleander (Ncrimn oleander), one of the oldest of cultivated orna- 
mental plants, the writer found in 1918 near Thermal. California, a branch bud 
mutation having variegated leaves borne by green-leaved plants, as shown in 
Plate 7, and uniformly variegated plants which liad been propagated from similar 
mutations. 



In Irish potatoes, Carriere(8) shows that many striking bud mutations 
occur which have been preserved through selection. East (19) records bud mu- 
tations as shown by the color, shape, character of eyes, and habit of growth, of 
the tubers which remained constant in propagation. Gilbert (26) says that the 
principal method of improving the Irish potato is through bud selection. 

In the sweet jiotato, H. C. Thompson, formerly horticulturist of the U. S. 
Department of Agriculture, in a personal statement in 1917 informed the writer 
that tliis plant is exclusively propagated vegetatively and that all commercially 
grown sweet potato varieties have originated as bud mutations. 

In apples, Hedrick ( 28) describes four strains which are now commonly 
accepted as varieties of the Twenty-ounce which originated as bud mutations. 
Farmer (23) describes the Oswego variety as originating as a bud mutation of 
the Northern Spy. Fletcher (24) gives an account of the Chesebro Spy variety 
which originated as a bud mutation of the Northern Spy. Mead (34) records a 
mutation of the Gravenstein variety having fruits with solid red color which has 
been propagated through bud selection. A seedless mutation of the Porter apple 
was discovered and called to the writer's attention l>y J. A. Dorrance at Scotland, 
Connecticut, in 1913. This consisted of one of the main limbs in an old tree. 
It has borne similar fruits each year since then and has been propagated. 
Beach ( 4 ) describes the Banks apple as a mutation of the Gravenstein variety, 
tlie Collamer as a sport of the Twenty-ounce, and the Red Russet and Olympia 
as mutations of the Baldwin variety. Castle (9) refers to two strains of the 
Wdiiams apple, one having conspicuously striped fruits and the other having 
nearly solid red color. Other striking mutations in apple varieties have been 
observed, an example of which is shown in Plate 8, including red and russet 
variations of the Rome (1, 2), oblong-shaped Grimes (1), solid dark-red varia- 
tions of the striped Ben Davis, and various shaped fruits in Baldwin apple trees 
observed by the writer at Seymour, Connecticut, during recent years in indi- 
vidual tree performance record plats of trees of these varieties in the J. H. Hale 
orchards. 

In peaches. Darwin (15) records peach trees producing buds which when 
developed into branches yielded nectarines and that six named and several un- 
named varieties of the peach have thus produced several varieties of the nec- 
tarine. Carriere ( 8 ) describes two varieties of the peach, the carnation-flowered, 
having a flesh-rose color, and the many-colored-flowered, possessing white striped 
colors, which originated as bud mutations. He also gives the willow-leaved red 
Madeleine and the laciniate-leaved red Madeleine as varieties originating as bud 
sports. Fletcher (24) mentions a white-fleshed clingstone or semi-freestone va- 
riety originating as a bud mutation of the Early Michigan. Powell (40) records 
the propagation of an early ripening mutation of the Mountain Rose peach. The 
writer found several branches in Elberta trees in the performance-record plat 
of this variety in the J. H. Hale orchards at South Glastonbury, Connecticut, in 
1912, bearing fruits without pubescence and otherwise apparently identical with 
fruits of the new J. H. Hale variety. Furthermore, branches were found in 



J. H. Hale peach trees bearing typical Elberta fruits, indicating that the J. H. Hale 
variety originated as a bud mutation. The writer also observed branch muta- 
tions in yellow-fleshed-fruited Elberta trees bearing white-fleshed fruits but other- 
wise like the Elberta fruits. 

In prunes, a large-fruited variety Coates No. 1418, an illustration of wliich 
is shown in Plate 9, originating as a bud mutation of the French prune, was 
described by the writer in 1919 (57). Coates propagates commercially no less 
than three varieties of the French prune which have originated as bud muta- 
tions (11). Darwin (15) records that a tree of yellow Magnum Bonum plum, 
forty vears old, produced a liranch mutation which liore red Alagnum LSonumfe. 

In grapes, Carriere (8) states that bud variation is comparatively common. 
Amongst other examples he cites the origin of the white seedless Corinth as a 
mutation from the parent seedy variety. Fletcher (24) records the King, a bud 
variety of the Concord. Paddock (37) gives mammoth or giant forms of the 
Concord identical with Eaton as originating from bud mutations of the Concord. 
Ballou ( 1 ) records a bud \ariety of the Concord with exceptionally large berries 
which came true under his observation for two successive crops. The Pierce 
variety originated as a bud mutation from Isabella, according to Le Long (33). 
The writer has photographed bud mutations of the Thompson seedless grape, as 
shown in Plate 10, with conspicuously large berries and different foliage than that 
of the parent form from the vineyard of C. L. Edmunds of Thermal, California. 
Roeding has introduced and propagates commercially a mammoth or giant 
Thompson seedless variety which he has stated to the writer originated as a 
bud mutation. 

In pears, Carriere (8) says that the following varieties have given by bud 
variation variegated varieties, Duchesse d'Angouleme, Amanlis, Guenette, Saint- 
Germain, Bergamotte d'Automne, Culotte de Suisse, and others. The writer 
observed and photographed in 1918 in commercial pear orchards near Tehachapi, 
California, limb mutations in Bartlett pear trees bearing striped fruits and in 
other instances fruits possessing very dififerent characteristics of shape, size, and 
color from the normal fruits on the same or neighboring trees, as shown in Plate 
11. Evidence was found to indicate that several of the strains of the Bartlett 
variety in those orchards, including the Winter Bartlett, the Sheep's Nose Bart- 
lett, and Corrugated Bartlett, originated as bud mutations. 

In strawberries, Farmer (22) states that the Pan-American, an ever-bearing 
variety, originated as a bud sport of the Bismark. 

An illustration of bud variation in the artichoke is shown in Plate 12. 

In citrus fruits, the investigations of the writer in Brazil in 1913 (17) indi- 
cate that the Washington Navel orange, a typical tree of which is shown in Plate 
13, one of the most important fruit varieties in existence, originated as a bud 
mutation of the Selecta variety at Bahia, Brazil, and was first propagated in 
1820. Reasoner (45) states that the Foster, a variety of grapefruit producing 
pink-colored fruits, originated as a bud mutation of the Walters variety. In a 
letter to the writer dated .August 6, 1915, Reasoner describes a pink-fleshed mu- 
tation of the Marsh grapefruit. A similar mutation was found bv the writer in 



10 

a Marsh tree on the L. V. W. Brown ranch at Riverside, CaHfornia, in 1919 (61). 
Conner (12) propagates commercially a variety of grapefruit, the Conner Pro- 
lific, which he states originated as a bud mutation of the Bowen. The writer has 
isolated through bud selection in the Marsh grapefruit variety, as grown in Cali- 
fornia, a mutation having conspicuously flattened and commercially seedless fruits 
(54, 66). An illustration showing a typical fruit of this strain is shown in Plate 
20. It is of much greater commercial value than the parent variety and is now 
being extensively propagated by nurserymen in California. 

In cotton, the Pima, the Yuma, the Gila, and the Somerton, improved long 
staple varieties, originated as mutations, according to Kearney (29, 30, 31), their 
originator, and are amongst the most important commercially in the United States. 

In tobacco, the writer (47) in 1904 in the Connecticut Valley originated the 
Hazlewood variety as a mutation of the Cuban variety. This variety has fur- 
nished the foundation for one of the important agricultural industries in America. 
In 1903 and 1904 the writer secured through the selection of mutations the Uncle 
Sam Sumatra, which is grown commercially in Florida. Georgia, and Alabama; 
the Halladay, which is extensively i^towii in the Connecticut \'alley, and other 
commercial tobacco varieties. 

In the cacti, Griffiths (27) records the origin of several spineless varieties 
as bud variations of spiny forms. 

In corn, Emerson (21) records the occurrence of recurring somatic varia- 
tions in variegated ears. De Vries (74) describes mass mutations in maize 
and (73) other forms of mutation, including unbranched varieties, loss of starch 
in the grains, and dwarf forms. East and Hayes (20) report various forms of 
somatic mutations in corn, including dwarf, bifurcated, and branched ears. 

In sugar cane, Carriere (8) mentions this plant as one which shows a large 
number of distinct bud varieties. Darwin (15) states that sugar cane is one of 
several plants that sometimes produce new varieties from the stock or root. He 
quotes Caldwell (7) as saying that the Ribbon cane has sported in Mauritius 
"into a perfectly green cane and a perfectly red cane from the same head. I veri- 
fied this myself, and saw at least 200 instances in the same plantation and the 
fact that completely upset all our preconceived ideas of the diil'erences of color 
being permanent. The conversion of a striped cane into a green cane was not 
uncommon, but the change into a red cane, universally disbelieved, and that both 
events should occur in the same plant, seemed incredible. I find, however, in 
Fleischman's 'Report on Sugar Cultivation in Louisiana for 1848' by the American 
Patent Office, the circumstance is mentioned, but he says he never saw it him- 
self." 

The Commissioner of Agriculture for the West Indies (35) reported several 
instances of striking bud mutations in sugar cane that had recently come to his 
attention, and presented colored illustrations of two of them. (An abstract of 
this article with black and white reproductions of the illustrations has appeared 
in the Journal of Heredity (39).) These observations were summarized as 
follows : 



11 

1. Bud variations occur in the sugar cane. 

2. They have been recorded from widely-separated countries, — Mauritius, 

Louisiana, West Indies, and Queensland. 

3. The difference between sport and mother-plant are often as considerable 

as those between recognized distinct varieties of the sugar cane. 

4. Bud variation may give rise to : — 

(a) Differently colored side shoots on one cane. 

(b) Differently colored canes in one stool springing from the same 

mother plant. 

(c) A cane with some joints striped and some unstriped. 

5. Plants grown from cuttings of the sports tend to come true to color. 

6. The cane giving rise to sports, whenever recorded, has been a strij^ed or 

ribbon cane. 

The observations of Other writers have disproven this last conclusion, as is 
shown by Deerr's account of the Home variety mentioned below. Some bud 
varieties of cane also show differences in hardiness and in sugar content. 

Deerr ( 16) states that the Lahaina and Bourbon varieties originated as bud 
mutations from the Mignonne variety. He records that the yellow-violet 
Cheribnn and purple-violet Cherihon varieties originated as bud mutations of the 
ribbon cherihon variety and that the white and black cheribon are bud varieties 
of the ribbon cane. Also that the White Tanna and Black Tanna varieties origi- 
nated as bud sports of the Striped Tanna. The Rose Bamboo and Purple Bam- 
boo varieties arose from mutations of the Striped Bamboo, and the Yellow Tip 
variety originated as a bud mutation of the Striped Tip. Deerr sa}s that the 
Home variety is of particular interest because it is one of the earliest, if not the 
earliest, recorded instance of a striped cane originating from a self-colored cane 
as a bud mutation. He also cites the Green Rose Ribbon variety originating as 
a bud sport of the Otaheite variety. In the striped cane known as the Tsimbec, 
a variety called the Iscambine rouge arose from a bud mutation. He says that 
the Branchu blanche is a self-colored sport from the Branchu rayee. Further, 
he records the case of green and yellow ribbon cane springing from the Yellow 
Caledonia. 

In December, 1890, Mr. John Home (35), then Director of Forests and 
Botanical Gardens, Mauritius, in a letter to the Director of the Royal Gardens, 
Kew, published in the Kew Bulletin for 1891, wrote: "'( )f new varieties orig- 
inating as bud sports we have eight or nine in Mauritius alone ; some of them 
very fine canes and they are extensively planted. Most of them are hardier than 
thei.- ])arents and they yield more sugar. They are mostly obtained from new 
canes recently introduced. The sudden change of climate, soil, and other circum- 
stances cause them to be thrown off. More of them might be obtained if the 
planters were more observing than they are and closely followed the cane cutters 
throughout their fields. As things are, a new variety is only observed should it 
chance to spring up in an outside row." 

The Hawaiian Sugar Planters' Association Experiment Station has collected 
a large amount of information showing the frequent occurrence of bud mutations 
in sugar-cane varieties grown in the Hawaiian Islands. 



12 

The writer is of the opinion that systematic economic bud selection work 
with sugar cane will give particularly early and striking results in the way of 
improved sugar production per acre, which will be worth millions of dollars 
annually to the industry. 

The simple elimination through bud selection of some of the undesirable 
strains arising from bud mutations in the established varieties will in itself 
achieve this result. This work can be carried on without any possibility of loss 
to the industry or the rearrangement of any of the methods of culture other than 
that of securing seed cane for planting. The cost of this work will be very 
small in comparison with its value. The increased production of sugar through 
the culture of uniform and superior varieties will be effected at no greater cost 
than that previously sustained when growing the more variable varieties with 
their resulting lower yields. 

In pineapples, the writer observed in May, 1920, amongst the plants in a 
commercial field of the Smooth Cayenne variety grown on the Island of Oahu, 
T. H., many apparent striking bud mutations. The leaves of some plants were 
smooth while others were sharply serrate. The shape of some of the fruits was 
cylindrical, while in other cases it was pyriform, ovate, obovate, globular, or 
modifications of these shapes. About 25 per cent of the plants had no fruits, 
while others were bearing fruits of different stages of ripeness. Some of the 
plants observed possessed a single crown, while others had multiple crowns. 
Frequent examples of plants having distinct strain characteristics, apparently 
originating as bud mutations, were found, indicating that bud variation is of 
common occurrence in this variety. 

The above list of varieties arising from bud mutations contains only a few 
of those on record. Furthermore, the recorded instances constitute only a small 
part of the total number of such cases. This condition exists to a large extent 
because most observers have not realized the possibility of the occurrence of bud 
mutations and their relation to the production of new varieties. For this reason 
it has been quite generally believed that bud varieties are fixed, and any new 
forms discovered in them have usually been ascribed to seed origin. Enough 
instances have been given to prove the importance of bud mutations in plant 
improvement work, and particularly so in the case of those plants which are 
vegetatively propagated. 

The Isolation of Strains in Established Varieties. 

Tlie term strain as here used designates a group of individuals of an agri- 
cultural variety differing from all other individuals of the variety in one or more 
constant and recognizable characteristics and capable of perpetuation. This dis- 
cussion will be largely confined to vegetatively propagated strains which in scien- 
tific literature are frequently referred to as clones, as suggested by Webber (76). 

Strains oftentimes arise from the unintentional propagation of bud muta- 
tions. For example, the writer and his associates have found in their study of 
the Washington Navel orange (64) that this variety as grown under California 
conditions has given rise to fourteen strains throug'h bud mutation within a few 



13 

bud generations. Typical fruits of some of these strains are shown in Plate 14. 
These strains for the most part have been unintentionally propagated by nursery- 
men and others. Some of them have been found to be very undesirable from 
the economic standpoint, while others apparently possess some value for par- 
ticular conditions of culture. 

\'arieties of economic value and importance often degenerate or run out 
through the unintentional or intentional propagation of undesirable strains origi- 
nating as bud mutations. In the Washington Navel orange variety as grown in 
California, the writer has found that the undesirable Australian strain, having 
rank-growing trees, an example of which is shown in Plate 15, which character- 
istically bear small crops of fruit of inferior quality, as shown in Plate 16, has in 
some instances been propagated to such an extent as to render the variety an 
unprofitable one. In a few cases the Australian strain has been intentionally 
propagated by nurserymen because of the vigorous, hardy growth of the trees 
and owing to a lack of knowledge of their fruiting habits. However, the propa- 
gation of the Australian strain has usually been unintentional. The trees of this 
strain produce unusual numbers of vigorous-growing branches, frequently called 
suckers. This growth was formerly highly prized and commonly used for the 
propagation of the Navel orange variety in California. Inasmuch as the supply 
of such bud-wood was much more abundant in Australian trees than in the high- 
yielding and desirable trees, budders naturally secured more bud-wood from the 
Australian than from the Washington or best strain trees where it was obtained 
without regard to fruit production. 

The isolation of the valuable strains of commercial varieties through bud 
selection is one of the important factors in plant improvement work. After 
strains have been isolated, their value for cultivation determined, and their char- 
acteristics recognized, they are frequently classed as agricultural varieties. 

In potatoes, Myers (36) reports the results of hill selection from high-yield- 
ing and low-yielding strains of potatoes in New York. The Cornell experiments 
showed a five-years' average yield of three low-yielding strains of 82 bushels per 
acre as compared with a five-years" average yield of three high-yielding strains 
of 208 bushels per acre. The increase in yield secured through bud selection in 
these experiments amounted to an average of 126 bushels per acre. Similar re- 
sults were obtained by Daniel Dean (36) of Nichols, N. Y., who began hill selec- 
tion with his variety of potatoes in 1904 and whose records show a difference in 
production in his high-yielding as compared with his low-yielding strains of 280 
bushels per acre in 1912 and 140 bushels per acre in 1913. The difference in 1913 
would have been greater except for an early frost. G. D. Brill in one year's hill 
selection work secured an increase of 107 bushels per acre as shown by the dif- 
ferences in yields of a high-yielding as compared with a low-yielding strain of 
the same commercial variety (36). 

The comparative yields of high- and low-yielding strains of the Carmen No. 3 
potato variety isolated through hill selection during 1904, 1905, and 1906, are 
reported by Waid {75) of the Ohio Agricultural Experiment Station. In these 
experiments the high-yielding strain produced a three-years' average of 774 



14 

bushels per acre as compared with an average of 492 bushels per acre for the 
low-yielding strain, and a yield of 607 bushels per acre secured from seed tubers 
selected without reference to individual hills. The high-yielding strain produced 
an average of 262 bushels jjer acre, or about 35 per cent more tiian the low- 
yielding strain, and 167 bushels ])er acre, or about 11 per cent, more than the 
check as the result of three years of bud selection work. His studies showed 
clearly that with few exceptions the low-yielding plants remained unproductive 
and that the high-yielding hills for the most part remained productive, as was also 
siiown to be the case in the Cornell experiments referred to above. 

In citrus varieties, the writer and his associates have recorded the behavior 
of 14 strains of the Washington Navel orange ((A) [typical fruits of some of 
these strains are shown in Plates 17, IS. and 19 1 ; 12 strains of the X'alencia 
orange (65) ; 7 strains of the Marsh grapefruit (66) [typical fruits of two of 
these strains are shown in Plates 20 and 21] ; 8 strains of the Eureka lemon (67) 
[typical fruits of three of the strains are shown in Plates 22. 23, and 24] ; and 6 
strains of the Lisbon lemon (68) [typical fruits of several strains are shown in 
Plates 25 and 26]. These strains originating as bud mutations have, for the most 
part, been unintentionally propagated. They have been found to be capable of 
perpetuation through bud propagation. The isolation of the valuable strains and 
the elimination of the undesirable ones through systematic bud selection has been 
demonstrated to be jjossible and commercially practicable. 

In timothy. \\'ebber ( 78 ) found great ditTerences experimentally and com- 
mercially in the yield of high- and low-producing strains isolated thrciugh bud 
selection. Kxperimentally. he shows that the high-yielding strains produced 
an average of more than six times the yield of the low-yielding strains. 

In ])runes. the writer has begun the study of the behavior of seven strains 
originating as bud mutations of the French prune variety in California; an 
exam])le of one of these mutations is shown in Plate 9. The data are incomplete 
as yet. but enough information has been secured to warrant the statement that 
these strains are very different in fruit and foliage characteristics and that these 
differences are of great con.imercial importance to the prune industry. 

In sugar cane, the writer and associates in the Hawaiian Sugar Planters' 
Experiment Station during 1920 found in fields of the H 109, the Yellow Cale- 
donia, and the D1135 \arieties many plants resembling distinct strains. Their 
appearance and occurrence indicated that they originated as bud mutations. The 
plant differences found in these strains included the number of stalks of each 
stool and their habits of growth, weight, length, circumference, shape, and color 
of stalks, amount of juice in the stalks and its sucrose content, and other impor- 
tant characteristics. These data are not complete as yet. nor available for pub- 
lication, but it is likely that they will be announced when these investigations 
have proceeded far enough to warrant this action. 

Most of the work in the isolation of strains has not been reported because 
such records have usually been withheld until the strains have been tested and 
introduced as varieties. In strawberries (5, 32), apples (41, 42, 43, 44), and 



15 

other crops such work has been reported upon, but the writer feels that it is not 
necessary here to quote them in order to demonstrate the importance of this 
work. The isolation of valuable commercial strains arising as bud mutations of 
established varieties in vegetatively propagated plants has been found to be prac- 
ticable, and it seems likely that the work can be made increasingly useful when 
once its importance is more generally understood. 

The Elimin.\ti<)N of Undesirable Str.mns. 

The undesirable strains in established commercial varieties arising from bud 
mutations include those in which the plants produce unsatisfactory and unprofit- 
able crops. For example, the Shade-tree strain of the b'ureka lemon, (67) an 
illustration of which is shown in Plate 27, which has been found by the writer 
and his associates to constitute more than 25 per cent of the population in some 
lemon orchards. The trees of this strain produce low yields of coarse thick-rind 
fruits, lacking in juice. The culture of these trees has been found to be un- 
profitable wherever investigated on account of their poor production. A number 
of lemon orchards have been continuously unprofitable from this cause alone. 
The elimination of the trees of the Shade-tree strain in established orchards 
through top-working them with buds secured from jjroductive trees of the de- 
sirable Eureka lemon strain, an illustration of which is shown in Plate 2H, has 
resulted in the development of heavy-bearing trees and profitable orchards. 

In established orchards or plantations where individual trees or plants of 
undesirable strains are discovered, such trees or plants can be successfully 
eliminated by top-working with carefully-selected buds or grafts secured from 
desirable parent trees, as shown in Plate 29, or by replanting with young trees or 
plants of a desirable strain. In the propagation of young trees or plants the 
elimination of the undesirable strains can be eiifected by using as parent trees or 
plants only those individuals which are known not to transmit the undesirable 
strain characteristics. 

The purity of commercial bud varieties can be maintained by eliminating or 
avoitling the propagation of the undesirable strains which frequently originate 
as bud mutations; examples of such mutations are shown in Plates 30, 31, and 32. 
The improved varieties of plants are the most valuable and precious possession 
of agriculture. Without selection most varieties are known to degenerate and 
run out, largely due to the appearance of undesirable and unprofitable strains. 
Therefore, the importance of purifying the proven an<l established varieties 
through the elimination of undesirable strains must be obxious to everv thinking 
and unprejudiced person. 

The Ameli(ir.\t](in of \',\rieties and Strains Through Bud Selection. 

The term amelioration of varieties and strains as here used may be defined 
as the keeping up or the bringing up of the average performance of the indi- 
viduals to that shown by the behavior of the best individuals in the variety or 
strain through bud selection. The writer is of the opinion that from a com- 
mercial standpoint this phase of plant improvement is the most important one of 



16 

all. This work can be accomplished ( 1 ) by means of individual plant perform- 
ance records whereby the best individual parent plants for propagation can be 
found, and (2) through the propagation of the superior plants selected on the 
basis of performance records and progeny tests. 

Individual Pl.-vnt Performance Records. 

Individual plant performance records for plant improvement work include 
systematic records, for as long a period as is found to be necessary in order to 
determine the inherent plant characteristics, of the quantity and commercial 
quality of the crop, the variability of the product, the season of production, the 
habit of growth of the plant, and any other data likely to be of value in judging 
the behavior and value of the plant. In order to illustrate this work the method 
of securing individual citrus tree performance records as carried on by the 
writer and his associates in southern California for the past eleven years will be 
briefly described (48, 49, 51, 64). There have been two phases in the evolution 
of this work — first, the investigational, and, second, the commercial. In the in- 
vestigational work carefully-selected plats of about one hundred full-bearing trees 
each were located in several of the best commercial orchards of the Washington 
Navel orange, the Valencia orange, the Marsh grapefruit, the Eureka and Lisbon 
lemon varieties. These locations were decided upon with particular regard to 
environmental influences and cultural conditions, so that reliable data of inherent 
tree characteristics could be secured. The location of two orchards in which the 
investigational tree performance records were secured is shown in Plate 55. 

Each individual tree in these plats was given a number so arranged as to 
both identify and locate it. This number was painted on the tree trunks with 
pure white lead paint, always in the same relative position and so as to be easily 
legible and conveniently found when desired. 

The fruits from each tree were picked by or under the immediate supervision 
of the writer or his associates by expert pickers for the entire period of the 
investigation. The fruits from each tree were studied immediately after picking, 
as shown in Plate 34. They were assorted into the standard commercial grades 
for the variety. The fruits of each grade were then assorted into the standard 
commercial sizes for the \ariety. The weight and number of fruits of each size 
in each grade were then carefully determined by the writer or his associates. So 
far as possible, the same man conducted this work in each plat every year in 
order to avoid differences due to the personal equation. After weighing and 
counting each lot, the fruits were examined for variations and the number of 
variable fruits of each class was recorded, as shown in Tables 1 and 2. During 
the course of this performance record work descriptions of tree and fruit char- 
acteristics were recorded. These studies were conducted on a total of 858 W'ash- 
ingfton Navel orange trees, 179 Valencia orange trees, 253 Eureka lemon trees, 
128 Lisbon lemon trees, 104 Marsh grapefruit trees, and a number of trees of sev- 
eral citrus varieties of minor commercial importance. These records covered periods 
of 4, 6, and 8 successive years, as the circumstances warranted, in order to carry 
out the purposes of this investigation. The work entailed a large amount of 



TABLE 1— OEANGE PEEFOEMANCE RECOED. 

DATE: Feb. 24, 1914. STEAIN: Washington. LOCATION: Higligrove, California. 

GEOWEK: National Orange Company. GEOVE: Vivienda. 

VAEIETY: Wasliinston Navel. PLOT: 3. ROW: 14. NO. OF TREE: 27. 



Notes: — Fine quality. 11% boxes. 







Orch.\rd 


Standard 


Culls 


Total 




Orehard 

Standard 

Culls 






946 






1 


58 


Number 






38 






! 






Total 








1,042 














300 
2SS 
250 
216 
200 
176 
1.50 
126 
112 
96 
80 


8 

19 

59 

133 

238 

167 

33 

11 

1 


6 
3 

7 

7 

16 

9 

8 
2 






14 






22 






66 






140 






293 


Number 




247 


Sizes 




175 






35 






11 






1 










Total 


946 


58 


38 


1,004 




Orcliard 

Standard 

Culls 






461- 8 










24- 7 


Weight 








17- 4 


Grades 












Total 








503- 3 












300 
2SS 
2.50 
216 
200 
176 
150 
126 
113 
96 
80 


1-10 

5- 6 

19-14 

51-15 

126-10 

125-12 

99- 6 

21-14 

8- 4 

0-13 


1- 1 




2 

6 

22 

54 

133 

130 

103 

23 

8 




11 






5 




2 
6 
4 
4 
1 




10 




8 




12 




11 


Weight 
Sizes 




6 


9 
8 
4 

n 




5 




14 






2 






4 






13 












Total 


461- S 


24- 7 i 17-4 


485 


15 



Australian 1 

Wrinkled 

Flattened 

Corrugated 

Protruding 3 

Yellow 

Ridged 3 

Ribbed 



SPORTS 

Creased 

Very smooth 

Coarse 

Raised section . . . . 
Sunken section . . . . 
Raised and sunken . 

Yellow section 

Golden nugget . . . . 



Abnormal shape 1 

Split navel 7 

Split side 3 

Pear shape 

Elliptical 

Long 

Striped 

Off bloom 



TABLE 2.— ORANGE PERFORMANCE RECORD. 

DATE: 19101915. STRAIN: Washington. LOCATION: Highgrove, California. 

GROWER: National Orange Company. GROVE: Vivienda. 

VARIETY: Washington Navel. PLOT: .3. ROW: 14. NO. OF TREE: L'7. 





Se.\.son 


Season 


Season 


Season 


Season 


Season 






1909-10 


1910-11 


1911-12 


1912-13 


1913-14 


1914-15 




Orchard 


738 


385 


581 


310 


946 


661 


604 


Standard 


19 


43 


57 


80 


58 


151 


68 


Culls 





38 


41 


311 


38 


165 


99 


Total 


757 


468 


679 


701 


1,042 


977 


771 





300 


















288 


10 


1 


14 


2 


14 


2 


7 




2.50 


36 





13 


6 


22 


4 


14 




216 


41 


2 


19 


34 


66 


21 


30 




200 


117 


6 


80 


43 


140 


49 


73 


Number 


176 
150 


141 
189 


13 
66 


72 
174 


77 
98 


293 

247 


98 
165 


116 
156 




126 


49 


15 


54 


80 


175 


252 


104 




112 


111 


98 


131 


25 


35 


120 


87 




96 


40 


135 


59 


15 


11 


69 


55 




80 


23 


94 


22 


10 


1 


32 


30 




Total 


757 


430 


638 


390 


1,004 


812 


672 




Orchard 


382- 7 


271-14 


315- 


152-14 


461- 8 


352- 2 


322.6 


Weight 
Grades 


Standard 


7-10 


75-15 


23-11 


34- 7 


24- 7 


78-12 


32.8 . 


Culls 


0- 


23-14 


16- 3 


103-12 


17- 4 


69-13 


38.5 




Total 


390- 1 


323-11 


354-14 


291- 1 


503- 3 


500-11 


393.9 




300 
















Weight 


288 


2- 9 


0- 4 


3- 5 


0- 7 


2-11 


0- 5 


1.6 


Sizes 


250 


11-12 








4 


2 


1-13 


6 


5 


1- 2 


4.2 




216 


15- 8 





12 


7 





11- 1 


22 


8 


7- 1 


10.6 


Expressed 


200 


48-11 


o 


S 


32 


11 


15-10 


54 


11 


18- 8 


28.8 


in ponndf 


176 


66-10 


6 


1 


32 


11 


32- 6 


133 


6 


41- 7 


52.1 


and 


150 


98- 


35 


7 


90 


1 


47- 6 


130 


5 


79- 5 


80.1 


ounces 


126 


28-14 


8 


7 


30 


2 


45- 1 


103 


14 


139-11 


59.3 




112 


70-11 


62 


2 


79 


13 


15-13 


23 


2 


73- 3 


.54.1 


Averages 


96 


28- 7 


98 


12 


41 





10- 


8 


4 


46- 3 


38.8 


in 
decimals 


80 


18-15 


85 


8 


17 


14 


7-12 


0-13 


24- 1 


25.8 


of lbs. 


Total 


390- 1 


299-13 


338-11 


187- 5 


48.5-15 


430-14 


355.4 


















11% b 


oxes 


11% boxes 





Notes: — Abrah.''.m Lincoln tree. Fruit is fine colored, large, and smooth. 



19 

systematic attention and required sustained effort. Some of these records are 
being continued in order to secure further and more complete information upon 
certain phases of tree behavior and additional data of some tree and fruit char- 
acteristics. 

These investigations have revealed the occurrence and frequency of bud 
mutations in the varieties studied, an example of which is shown in Plate 35, the 
existence and extent of occurrence of the various strains arising from bud muta- 
tions and their comparative commercial value, the tree and fruit characteristics 
of the trees of these strains, and other information of fundamental importance 
to the citrus industry. In the course of this work improved methods of propa- 
gation have been discovered and developed, such as the use of fruit-bearing bud- 
wood for propagation, an example of which is shown in Plate 36, instead of the 
sucker growth which was formerly used for this purpose. Illustrations showing 
the method of using this bud-wood in propagation are shown in Plates 37 and 38. 
Iudi\idual tree performance records of pruned and unpruned trees of each of 
the commercially important varieties led to the discovery of the very injurious 
and disastrous effects of early or severe pruning ( 35, 58, 63 ) with healthy, 
normal citrus trees. This information has resulted in the general abandonment 
of such practices amongst citrus growers. The individual tree records, showing 
the behavior of trees grown under different methods of soil fertilization, led to 
the origination by the writer of an improved system of applying organic ferti- 
lizers in citrus prchards called the furrow-manure method {53, 56, 62), which 
has proven to be more economical and efficient than any formerly used. A study 
of the behavior of the fruits from the lemon performance-record trees in curing 
rooms led to the discovery of the importance of a uniform condition of atmo- 
sphere humidity in the curing of lemons and other citrus fruits and to the inven- 
tion of a humidifier for securing and maintaining the optimum conditions (50, 
59). (Jther results might be cited, but the above are considered to be sufficient to 
show the importance of this work. 

The results of the investigational citrus tree performance record work nat- 
urally led to the development and use of commercial tree performance record 
work by citrus growers for the following purposes : ( 1 ) to locate drone trees of 
undesirable strains in the established orchards for top-working or replanting; 

(2) to liicate, if jjossible, superior trees as sources of bud-wood for propagation; 

(3) to determine the results of cultural experiments or tree treatments; and 

(4) to carry on intelligent individual tree care in the orchards. Up to the present 
time, 1921, commercial tree records have been kept in more than 50,000 acres of 
citrus orchards in California and in considerable citrus acreages in southern Ala- 
bama and in Florida. 

In commercial citrus tree records the yield of the individual trees in weight 
or number of boxes of fruit are recorded by the foreman of the picking crew or 
some other person at the time of picking, as shown in Plate 39. Notes are made 
as to the production of any striking variations observed in the fruits or the trees. 
In the in\-estigational record work it was found that there is a definite correla- 



20 

tion of the amount of yield and the commercial quality of the fruits, the highest 
yielding trees usually producing the highest proportion of first-grade fruits of 
the most desirable commercial size. From the commercial records of individual 
tree production for a reasonable period, a classification of the trees with regard 
to their value for cultivation can be made, the undesirable trees top-worked or 
replanted, trees located for individual care and attention as needed, superior 
trees, if any be found, located as sources of bud-wood for propagation; and the 
results of tree treatments definitely determined. 

The Commercial Utilization of Individual Plant Records. 

The commercial plant records may be utilized in the origination of new 
varieties, the isolation of valuable strains, and in the amelioration of strains 
and varieties. The manner in which this utilization is effected in the citrus 
industry in California will be briefly described (60). 

The California Fruit Growers' Exchange, a cooperative non-profit organi- 
zation of more than ten thousand citrus growers, established in May, 1917, a 
bud department of the Fruit Growers' Supply Company, which is a subsidiary 
organization furnishing materials and orchard supplies of all kinds to the mem- 
bers of the Exchange at cost. The bud department was established for the pur- 
pose of carrying out commercially the results of the investigational individual 
tree performance record work in the citrus fruits. In order to make this service 
available to the citrus industry as a whole it was provided by the Exchange that 
the bud department should supply reliable buds secured from superior parent 
trees, selected on the basis of their performance records, to all persons desiring 
them, whether they were members of the Exchange or not. In this way the 
work of the bud department is a public service. Within three years since the 
founding of the bud department it has furnished more than a million selected 
buds to propagators at a cost of five cents each to members of the Exchange, 
and for six cents each to non-members. The buds have been chiefly used by 
nurserymen in the propagation of nursery trees and to a less extent by growers 
for top-working undesirable trees in established and bearing orchards. The buds 
have been secured, for the most part, from superior parent trees found in the 
best citrus orchards existing in California. The parent trees have been selected 
as sources of bud-wood from a study of the commercial individual tree per- 
formance records in these orchards and in some instances from the best trees in 
the investigational performance record plats previously studied by the writer. 
This bud department has been a success and self-sustaining from its beginning. 
The young trees in the orchards grown from these buds and others selected and 
distributed by the writer during preceding years have produced earlier and more 
uniformly good crops of fruit than trees in comparative orchards which were 
propagated in the ordinary way. The value of this improved production, due to 
bud selection at this time, has been estimated by Mr. G. H. Powell, general man- 
ager of the California Fruit Growers' Exchange, to amount to more than one 
million dollars annually. In connection with the work of securing and dis- 
tributing selected citrus buds, the bud department maintains an experimental 



21 

citrus nursery for the study of problems in budding, stocks, and other phases 
of propagation. It also furnishes to growers reliable information as to the 
adaptation of citrus varieties to local soil and climatic conditions, accurate data 
as to the production of the varieties and the relation of this production to market 
conditions, and other information of value to the prospective planter or the 
established grower. 

Potato growers in Maine, California, and in several other States have or- 
ganized successful cooperative associations for the purpose of making available 
commercially the results of bud selection work in potato varieties. 

Other associations of growers or propagators in industries founded upon 
varieties of plants originated as mutations are in operation at this time. Amongst 
these may be mentioned the Arizona-Egyptian Cotton Growers' Association, the 
New England Tobacco Growers' Association, and the Nurserymen's Bud Selec- 
tion Association of California. 

The Selection of Superior Parent Plants. 

The selection of superior parent plants for propagation can be made on the 
basis of individual plant performance record data and the intimate knowledge 
of plant characteristics gained in the course of the plant performance record 
work. 

In the citrus, the selection of superior parent trees is made after an ade- 
quate number of performance records have been secured. Only the high-yielding 
trees producing the best commercial fruits are considered as sources of bud-wood. 
If the records or other observations show the production of any markedly off- 
type fruits or striking variations, such trees are immediately discarded from fur- 
ther consideration as sources of bud-wood for propogation. Only those high- 
yielding trees which consistently produce uniformly good fruits are selected as 
parent trees. 

Progeny Tests. 

The bud-wood from each parent citrus tree is kept separate. The buds from 
each parent tree are used in separate blocks so identified in the nursery that 
the progenies can be traced back to the individual parent trees. Examples of 
the fine growth and early fruiting habits of such trees are shown in Plates 40 
and 41. When the nursery trees are transplanted each progeny is kept separate, 
and wherever possible the trees of each progeny are planted in the orchard so 
that at any time the behavior of any progeny and its parent can be studied. In 
this manner, as well as through additional experimental progeny tests now under 
way, the transmitting power of the parent trees can be determined. In the 
California citrus industry the foundation has been laid for the future selection 
of parent trees on the basis of progeny records. It is probable that through this 
work the most reliable sources of propagating material will be secured that has 
ever been attained in any industry in the history of agriculture. In this con- 
nection it may be stated that in addition to extensive cooperative commercial 
progeny tests the writer and his associates are keeping investigational individual 



22 

tree-performance progeny records with 5,464 lemon trees, 450 orange trees, and 
about 500 trees of other citrus varieties. As soon as funds can be secured for 
this work, the number of trees where investigational records are kept will be 
greatly increased. 

Similar investigational and commercial progeny tests to those carried on in 
the citrus are also being conducted with cotton, tobacco, corn, oats, wheat, flax, 
timothy, and varieties of other agricultural crops under different auspices in 
various agricultural districts of the United States. 

The Hawaiian Sugar Planters' Experiment Station in 1920 made a begin- 
ning of progeny test work with selected plants of the Yellow Caledonia, H 109, 
D 1135, and other sugar cane varieties grown in the Hawaiian Islands. The 
purpose of this work is to establish and maintain reliable sources of propagating 
material. 

The Scientific Studv of Bud Mutations and Bud Selection. 

The overshadowing interest amongst scientists in the study of the phenome- 
non of sexual variations in ]>lants and the behavior of seedlings grown from 
these variations during the past century, has resulted in the partial neglect of the 
equally interesting and important field of the investigation of bud mutations and 
the characteristics of plants originating from them. 

As the writer sees it, the scientific problems in this connection include a 
study of the extent and frequency of bud mutations in all of the agricultural 
varieties, an investigation of the fundamental causes of the phenomenon of bud 
mutation, and the development of improved methods of propagation. This in- 
vestigational work should precede and lay the foundation for the commercial 
work. While this arrangement may apparently delay the utilization of bud 
selection, it may, as a matter of fact, hasten the time when economic results can 
be obtained. The scientific studies of bud mutations, their origin and develop- 
ment, will probably result in the discovery of simplified methods of bud selection 
and insure protection from disappointments due to operations founded upon 
defective plans based upon incomplete knowledge leading to premature and 
oftentimes erroneous conclusions. In some instances it may be found to be 
feasible to carry on the investigational and the commercial work simultaneously. 
The writer believes that such is the case in the work for the improvement of 
sugar cane through bud selection. As the result of an experience covering more 
than twenty years in both the investigational and commercial work of plant 
breeding, the writer wishes to emphasize the necessity for scientific studies in 
this connection in order to discover the underlying principles of bud mutation 
and bud selection as a means for establishing this work in every instance upon 
a sound and lasting foundation. 

P10NEER.S IN Bud Mutation and Selection Work. 

It seems fitting in this pajier to refer to the pioneer students of Ijud \ariation 
and bud selection. No attempt will be made here to mention all of the men who 
have been concerned in this activitv. These names include Carriere, Darwin, 



23 

De Vries, Cramer, Babcock, Bailey, Castle, Collins, Cook, Dorsey, Galloway, 
Kearney, Shull, Stout, Swingle, and Webber. Of the men who have been more 
particularly concerned in the introduction and development of commercial bud 
selection work, the following names may be mentioned : Powell, Burbank, Fraser, 
Chase, Winberg, Farmer, Coates, and Milliken. To this list many other names 
of important workers might be added, but the writer considers that sufficient 
names have been given to indicate the type of workers concerned in this work. 



The fundamental factors in the economic work for the improvement of 
plants through bud selection arc ( 1 ) the development of new and important 
varieties originating from bud mutations; (2) the isolation of valuable strains 
of established varieties originating as bud variations; and (3) the amelioration 
of the cultixated varieties and strains by bringing up their average production to 
as nearly that of the best individuals in them as may prove to be possible through 
the systematic selection and propagation of superior parent plants. 

The experience and achievements to date in both the investigational and 
coinmercial work for the improvement of plants through bud selection, warrant 
the belief that much greater progress along these lines may be expected in the 
future than has been accomplished in the past, when the possibilities of this work 
become more generally recognized and more fully understood. 

The writer believes that in the plants with which he is familiar, asexual and 
sexual reproduction are fundamentally alike in respect to the extent and range 
of variation, and that equally valuable results have been achieved and may be 
expected in the way of plant improvement from bud selection as has been the 
case with seed selection. 



LITERATURE CITED 



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Exp. Sta. Circ. 94. 
Ballou, F. H. 1917. Letters to C. S. Pomeroy, U. S. Dept. Agr. 
Batbson, William. 1902. Mendel 's Principles of Heredity. 
Beach, S. A. 1905. The Apples of New York. N. Y. Agr. Exp. Sta. Rept. 1903, 

Part 2. 
Beatty, F. E. 1905. Improving Strawberries by Selection. In Proc. 2nd meeting 

Am. Breed. Asso., Feb., Rept. v. I, pp. 107-108. 
BoSHNAKIAN, S.\RKIS. 1916. Breeding Neplirolepis Ferns. Jour. Hered, v. 7, no. 5, 

pp. 225-236, figs. 18-25. 
CALD^VELL, J. 1874. Sports in Sugar Cane (in Mauritius). Gardeners Chron., p. 316. 
Carrikre, E. A. 1865. Production et Fixation des Varietes dans les Vegetaux. Paris. 

lUus. 
Castle, W. E. 1914. Pure Lines and Selection. In Jour. Hered., v. 5, no. 3, pp. 

93-97. March. 
Castle, W. E. 1917. The Role of Selection in Evolution. In Jour. Wash. Acad. Sci., 

V. 7, no. 12, pp. 369-387. June 19. 
CoATES, Leonard. 1920. Prunes. In Catalog, Coates Nursery Co., Inc., Morganhill, 

Calif., pp. 12-13. 
Cramer, P. J. S. 1907. Kritische Uebersicht der bekannten Falle von Knospenvaria- 
CoNXOR, O. W. 1915. Connor Prolific Grapefruit. In Catalog Ocklawaha Nurseries, 

1916. Tangerine, Fla., pp. 34-33. Illus. 
Cramer, P. J. S. 190". Kritische Uebersiclit der bekannten FiiUe von Knosjienvaria- 

tion. 
Darwin, Charles. 1859. The Origin of Species by Means of Natural Selection. 
Darwin, Charles.. .1868. The Variation of Animals and Plants under Domestication. 

(2nd edition, N. Y., 1900, 2 vols.) 
Deebr, Noel. 1911. Cane Sugar. London. Illus. 
DORSETT, P. H. ; Shamel, a. D., and Popenoe, Wilson. 1917. Origin and History 

of the Navel Orange of Bahia. In The Navel Orange of Brazil with Notes on Some 

Little Known Brazilian Fruits. U. S. Dept. Agr. Bui. 445, pp. 1-3. 
Dorset, M. J. 1917. The Inheritance and Permanence of Clonal Varieties. In 

Proc. 13th Ann. Meeting Am. Soc. Hort. Sci., N. Y., pp. 41-71. Dec, 1916. 
East, E. M. 1910. The Transmission of Variations in the Potato in Asexual Repro- 
duction. Conn. Agr. Exp. Sta. Rept. 1909-10, pp. 119-160, pi. 5. 
and Hayes, H. K. 1911. Inheritance in Maize. Conn. Agr. Exp. Sta, 

Bui. 167, 142 p., 35 fig. 
Emerson, R. A. 1913. The Inheritance of a Recurring Somatic Variation in A'arie 

gated Ears of Maize. At Am. Soc. Naturalists, Cleveland, 0., Jan., 1913. In Am 

Nat., V. 48, no. 566, pp. 87-115, fig. 3. Feb., 1914. 
Farmer, L. J. 1911. Fall Bearing Strawberries. In Farmer on the Strawberry. 

Pulaski, N. Y., pp. 67-68. 
Farmer, L. J. 1918. The Oswego Apple. In Spring and Fall Special Price List 

p. 14. 
Fletcher, S. W. 1910. Mich. Agr. Exp. Sta., Spec. Bui. 44; Chesebro Spy Apple, p, 

11; Davidson Peach, p. 35; King Grape, p. 68. 
Gersdorfp, Chas. E. F. 1919. A Partial List of Roses Introduced in America. In 

The Am. Rose Ann., pp. 134-147. 
Gilbert, A. W. 1917. The Potato. New Y'ork. 
Griffiths, David. 1913. Behavior, under Cultural Conditions, of Species of Cacti 

Known as Opuntia. V. S. Dept. Agr. Bui. 31, 24 p., 1 fig., 8 pi. 
<28) Hedrick, U. p. 1915. Remarkable Sports of the Twenty-Ounce Apple. The Rural 

New Yorker, v. 74, no. 4307, p. 722. May 22. 



25 

Keabxet, T. H. 1910. Breeding New Types of Egyptian Cotton. U. S. Dept. Agr., 

Bur. Plant Indus. Bui. 200. 
Kearney, T. H. 1914. Mutation in Egyptian Cotton. Jour. Agr. Eesearoh, v. 2, 

DO. 4, pp. 287-302, pi. 17-25. July 15. 
Ke.\rney, T. H. 1918. A Plant Industry Based Upon Mutation. Jour. Hered., v. 9, 

no. 2, pp. 51-61, figs. 1-8. Feb. 
Kellog, E. M. 1902. Bud Variation in the Strawberry Plant. Inter. Conf. Plant. 

Breed, and Hybrid., N. Y. In Eept. N. Y. Hort. Soe., v. 1 
Le Long, B. M. 1891. The Pierce Grape. In Calif. State Board Hort. Eept., 1891, 

pp. 131-132, 1 col. pi. 
ME.A.D, H. O. 1916. A Eed Gravenstein Apple. In The Eural New Yorker. March 4. 
Mokris, D. 1901. Bud Variation in the Sugar Cane. In West Indian Bui., v. 2, 

no. 3, pp. 216-223, 2 col. pi. 
Myers, C. H. 1914. Improving the Potato Crop by Selection. Cornell Ecading 

Courses, v. 3, no. 68, pp. 229-248, figs. 121-133. July 15. 
Paddock, W. 1896. Bud Variation of the Concord Cirape. In Gard. and For., v. 9, 

p. 464. Nov. 18. 
Pierson, Wallace E. 1918. Eose Families and Their Tendencies. In The Am. 

Rose Ann., pp. 99-100. 
Pomeroy, C. S. 1919. Bud Variations in Sugar Cane. Jour, of Hered., v. 10, no. 3, 

pp. 129-135, figs. 16-17. March. 
Powell, G. H.\rold. 1898. Plant Breeding: Its Application Through Bud Selection 

to the Improvement of Varieties. In Amer. Gard., v. 19, pp. 466-467, 514-515. 

July 14. 
Powell, G. T. 1902. Bud Variation in the Apple. Inter. Conf. Plant. Breed, and 

Hybrid., N. Y. In Eept. N. Y. Hort. Soc, v 1. 
Powell, G. T. 1908. $1000 an Acre from Pedigreed Trees. In Country Life in Am., 

V. 13, no. 5, pp. 504-6, 538, 540. Illus. 
Powell, G. T. 1916. Transmitting Productive Qualities in Fruit Trees Through Bud 

Selection. West. N. Y. Hort. Soc. (Eoehester). 
Powell, G. T. 1920. Thirty Years' Experience in Application of Bud Selection in 

the Fruit Industry. Asso. Calif. Nurserymen, San Francisco. In Calif. Citrograph, 

v. 5, no. 11, pp. 344, 364-6. Illus. Sept. 
Eeasoner Bros. 1914. Foster Grapefruit. In Catalog Eoyal Palm Nurseries, 1915, 

Oneco, Fla., p. 11, 2 illus. (1 col.). 
EoEDiNG, Geo. C. 1919. Euonymus. In Catalog Fancher Creek Nurseries, Fresno, 

Calif., p. 15. 
Shamel, a. D. 1907. New Tobacco Varieties. In V. S. Dept. Agr. Yearbook 1906, 

pp. 387-404, figs. 11-14, pi. 33-36. 
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Calif. Fruit. Gr. Conv., pp. 89-105. March 8. 
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Bui. 494, 10 p.. 7 fig. Jan. 
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26 

Shamel, a. D. 1919. Some Kosults frcnn an Exiierinient witli Pruning as Comparcil 

with No Pruning of Full-Bearing Washington Navel Trees. In Calif. Citrograph, 

V. -1, no. 7, pp. 174-175, 3 fig. May. 
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Shamel, A. D. 1920. Origin of a Grapefruit Variety Having Pink-Colored Fruits. 

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1909-1910. Chicago.) 
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pp. 465-467. 
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Asso., v. 3, pp. 191-198. 
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V. 18, pp. 501-503. 
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pp. 347-357. 
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Cornell Univ. Agr. Exp. Sta. Bui. 313, pp. 337-392, fig. 86-96, pi. 1-10. April. 



EXPLANATION OF PLATES 



Plate. 

1. Branches of the variegated Shrubby Althea or Rose of Sharon (Hibiscus syriacus) 

showing solid green-leaved branches arising as bud variations. Riverside, Gal. 

2. Variations in a Dahlia plant which have persisted during the five years of the life of 

the plant. The normal color of the flowers is deep velvety red, and the variations 
are white and pinkish white. Riverside. Cal. 

3. Dahlia flower of Le Grande Manitou variety and a bud variation found on a jilant of 

tliat variety. Riverside, Cal. 

4. A branch of Euonymns jnponica showing the bud origin of the silver-variegated horti- 

cultural variety argenteo-variegatus. Several, if not all, of the other sub-varieties 
of this plant originated as bud mutations. Riverside, Cal. 

5. Branches of Pittosporum tobira var. variegatum, showing green- and w-hite-leaved bud 

variations. Riverside, Cal. 
ti. A bush of Pittosporum tobira var. rarivijulum. which has several green-leaved and 
white-leaved branch sports. Riverside, Cal. 

7. Branches of the oleander {Nerium oleander) showing (right) the normal green 

foliage and (left) a variegated form found as a branch variation in the same 
bush. Thermal, Cal. 

8. Winter Banana apples, showing a red and two large fruits occurring as lindi variations. 

C. H. Whittum, Eaton Rapids, Mich. 

9. Prunes from a single tree of a new bud strain, the Coates 1418. Up]ier right, typical 

Coates 1418; lower right, typical ordinary French prune; left, four Coates 1418 
and one ordinary French. Morgan Hill, ('al. 

10. Thompson Seedless grapes, showing (left) the normal fruit ami (right) a large- 

fruited form discovered as a bud nuitation and propagated by its owner. Thermal, 
Cal. 

11. Bartlett Pears, showing (right) ordinary strain, (center) oblong strain, ami (left) 

sunken section occurring as bud variations. Tehachapi, Cal. 

12. Leaves and flower buds (the edible portion) of two strains of the common artichoke 

(Cynara scolymus) found on neighboring jdants and doubtless resulting from a 
bud variation. Riverside, Cal. 

13. A representative tree of the Washington strain of the Washington Navel orange, 

bearing heavy crops of high-grade fruit. Highgrove, Cal. 

14. Fruits showing variations occurring on a single tree of the Thomson strain Washing- 

ton Navel orange. These variations have been propagated and each of the two 
progeny trees are producing fruit of the same character as their several bud 
parents, showing these forms to be true mutations. Highgrove, Cal. 

15. Characteristic trees of the Australian (left) and Washington (right) strains of the 

Washington Navel orange. Highgrove, Cal. 

16. A typical fruit of the Washington Navel orange variety and an Australian fruit found 

as a limb sport in the same tree. Highgrove, Cal. 

17. A basket of Washington Navel oranges from a tree of the Washington strain. River- 

side, Cal. 

18. Fruits of the Corrugated strain of the Washington Navel orange occurring as a limb 

mutation in a tree of the standard strain. Highgrove, Cal. 

19. Fruit of the Dry strain of the Washington Navel orange, occurring as a liranch muta- 

tion in a tree of the standard strain. Riverside, Cal. 

20. Typical fruit of the Marsh strain of the Marsh seedless grapefruit. Note the desirable 

shape, thin skin, fine texture, and seedless character. Highgrove. Cal. 

21. A fruit of the Seedy strain of the Marsh grapefruit. Highgrove, Cal. 



28 

22. A few of the Eureka lemon tyfies that frequently occur as buil variations on a single 

tree. Corona, Cal. 

23. Branches of the Variegated Eureka lemon showing the characteristic markings of 

fruits, leaves, and young twigs. This strain originated as a branch mutation and 
has been propagated through three bud generations. Corona, Cal. 

24. A Navel lemon found as a bud variation on a tree of the Eureka variety. Escondido, 

Cal. 

25. Typical lemons of the Lisbon strain, the type of the Lisbon variety. Five other 

strains of this variety have been found as bud variations, recorded and propagated 
during the bud selection work of the V. S. Department of Agriculture. Corona, 
Cal. 

26. Lisbon lemons showing pronounced variations occurring iin a single tree of an inferior 

strain. Corona, Cal. 

27. A typical tree of the Shade Tree strain of the Eureka lemon. The trees of this strain 

are vigorous and rapid in growth but low in production and bear fruits of a low 
grade. Corona, Cal. 

28. A young Eureka lemon tree of the Eureka strain. Note the productive condition of 

the tree and the tine type of fruit. Corona, Cal. 

29. Marsh grapefruit top-worked on an undesirable tree. Highgrove, Cal. 

31). Buby Blood oranges showing typical fruit and others from a branch mutation, showing 
various stages of dryness, the most of the fruit being entirely dry. Nearby trees 
bore heavy crops which were all of the Dry strain. Corona, Cal. 

31. Branch from a Buby Blood orange tree showing the occurrence of a Navel fruit as a 

bud variation. In this way the Bahian Navel orange is frequently found in 
Brazil as bud mutations in trees of the Seleeta variety. Corona, Cal. 

32. Thomson orange tree in which the entire upper part and right side are barren every 

season, the lower left portion bearing normally. Eiverside, Cal. 

33. Washington Navel orange orchards along the foothills, showing two orchards in which 

individual tree performance records were secured in the investigational work of the 
U. S. Department of Agriculture. Highgrove, Cal. 

34. View in a Washington Navel orange orchard showing the method of grading, sizing, 

weighing, and recording the production of individual trees in the investigation per- 
formance record work of the U. S. Department of Agrieultiu'e. Highgi-ove, Cal. 

35. Typical flowers of the Washington strain and the Seedy strain of the Washington 

Navel orange. Note the abundance of pollen produced by the anthers of the 
Seedy strain, while the flowers of the Washington strain do not proiluce pollen. 
Biverside, Cal. 

36. View in an Eureka lemon tree, showing the type of fruit-bearing bud-wood advised 

for use in propagating from select parent trees. The leaves have been cut from 
one twig in order to show its characteristics to better advantage. Corona, Cal. 

37. Citrus propagation: Cutting a biul from a typical bud-stick of fruit-bearing wood for 

insertion into the seedling stock. 
3S. Citrus propagation: Steps in the budding of a citrus nursery tree (from left to right) : 
seedling stock; inverted T-shaped cut for bud; bud inserted; inserted bud wrapper! 
with waxed cloth; budding knife. Eiverside, Cal. 

39. View in a Washington Navel orange orchard, showing the method of securing com- 

mercial individual tree performance records in this 1500-aere planting. Highgrove, 
Cal. 

40. Two-year-old Eureka lemon nur.sery ]n-opagated from selected fruit-bearing bud-wood. 

showing the fine tree development and the early fruiting tendency. Eedlands, Cal. 

41. Eureka lemon tree, 2 years 9 months old, propagated from select performance record 

trees. Note fruitful condition and fine character of fruit. Clarcmont, Cal. 



I 





I'lato 2. Variations in a Dalilia plant wlii.-li have ]HTsistea .luring the tive years of the life 
of the plant. The normal color of the llowers is deep velvety re.l ami the variations 
are white and pinkish white. Riversiile, Calif. 




Plate i. A branch of Euoniimiis jiiiiniiicd. showing the Innl orifjin cif the silver- variegated 
horticultural variety iiriiiiili u-Kniiinitux. Several, if not all, of the other sub-varieties 
of this plant originateil as bud mutations. Riverside, Calif. 




Plate o. Brandies of Fittonponnn liihira var. rariiiiatnm, sliinving green- ami wbite- 
leaveil bud variations. Eiversiile, Calif. 




- % 




I'late 12. Lcavos and flower bvuls (tlio eiliblo |ioitioii ) of two strniiis of tlio roiiimoii aiti- 
flioke {Ci/narit scoliiiiiii.s) foninl on lu-igblioiiiiy plants ami iloiibtless resolting' from a 
bud variation. Eivorside, Calif. 




Plate 13. 



A represeutative tree of tlie Washington strain of the Washington Navel orange, 
bearing heavy crops of high-grade fruit. Highgrovej Calif. 




Plate 21. A fruit (if the Seedy strain of the Marsli grapefruit. Highgrove, Calif. 




Plate ■2-2. A ivw of tlir Kuirk:i k-iiioii t.v|H's that frequently o.-iiir a- lunl \aiiati 
single tree. Corona, Calif. 




I'late 23. Branelies of the Variegated Eureka lemon, sliouing the charafterisiic markings 
of fruits, leaves, and young twigs. This strain originated as a branch mutation and 
has been propagated through three bud generations. Corona, Calif. 




Plate 26. Lislion 



showing pronounceil variations oi-ciirriiiji 
inferior strain. Corona, Calif. 



sintik' tree of an 




Plate 17. A 
sti'aiii aii- 
low grade 



^'''■■'1 '"'■ "I' '!"■ ^^'■'■i'' 'I'l'i' -iiriin Ml' the Kurrka leiiicu. The trees of tli 
liuorous ami raiii.l in yruwth Imt luw ill iiroiluetiuu, ami bear fruits of 
Corona, Calif. 




Plate 28. A youug Eureka lemon tree of the Eureka strain. Note the ]iro.lui-ti%-e 
condition of the tree and the tine type of fruit. Corona, Calif. 




Plato 29. llarsU grapefruit top-w-orkoil on an nndesirablo trt'O. Higligmve, Calif. 




Tliomsou orange tree in whii-li tlii> entire upjjer part" and right side ar 
•ery season, the lower left portidn bearing normally. Riverside, ('alif. 







5 bj5 

=.3 




Plate 36. Vit'w iji hii Kurcka lonioii trie. Nliowiiiu- the ty|ie of fniit-lioaring liiiil-wooa 
adviseil fur use in iiropauatinu; f,oiii schM-t parent trees. The loaves liave lieen eut 
from one twig in or.ler to sliovv its cliar.-ieter to better ailvantatie. (.'orona, Calif. 




J'hitc :^7. Citrus propagatiim : Ciittiiig a Inul t'ldm a ty]iical lnnl-stii-k of fruit bearing 
wood for insertion into the see'lling stoek. 




Plate oS. Citrus iinipagation. Steps in tlie Imililing uf a citrus luirsery tree ( freiii li'ft t" 
right): seedling stock, inverted T-shapeil cut for bud, bud inserted, inserted l>uil 
wrapped with waxed cloth, budiliug knife. Riverside, Calif. 




Plate 40. Two-year-old Eureka lemon nursery propagated from selected fruit-bearing bud- 
wood, showing the fine tree development and the early fruiting tendency. Bedlands, 
Calif. 



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